An antibiotic selected from the group consisting of Tumimycin and salts thereof. This antibiotic is an orange-red powder having the following average elemental analysis: carbon, 66.79 percent; hydrogen, 6.85 percent; nitrogen, 3.45 percent; and an infrared absorption spectrum as shown in FIG. 1 and an NMR spectrum as shown in FIG. 2. Tumimycin is useful as an antimicrobial agent.
